Question: Which Class IB flammable liquid ester has the lowest vapor pressure?
Paraphrase: What Class IB flammable liquid ester possesses the vapor pressure that is lowest?
SPARQL (Wikidata): select ?ent where { ?ent wdt:P31 wd:Q21009055 . ?ent wdt:P2119 ?obj . ?ent wdt:P31 wd:Q101487} ORDER BY ASC(?obj)LIMIT 5 
Answer: ethyl acetate, butyl acetate, ethyl acetate, propyl acetate, methyl methacrylate